O'Hara P J, Grant F J, Haldeman B A, Gray C L, Insley M Y, Hagen F S, Murray M J
Proc Natl Acad Sci U S A. 1987 Aug;84(15):5158-62. doi: 10.1073/pnas.84.15.5158.
Activated factor VII (factor VIIa) is a vitamin K-dependent plasma serine protease that participates in a cascade of reactions leading to the coagulation of blood. Two overlapping genomic clones containing sequences encoding human factor VII were isolated and characterized. The complete sequence of the gene was determined and found to span about 12.8 kilobases. The mRNA for factor VII as demonstrated by cDNA cloning is polyadenylylated at multiple sites but contains only one AAUAAA poly(A) signal sequence. The mRNA can undergo alternative splicing, forming one transcript containing eight segments as exons and another with an additional exon that encodes a larger prepro leader sequence. The latter transcript has no known counterpart in the other vitamin K-dependent proteins. The positions of the introns with respect to the amino acid sequence encoded by the eight essential exons of factor VII are the same as those present in factor IX, factor X, protein C, and the first three exons of prothrombin. These exons code for domains generally conserved among members of this gene family. The comparable introns in these genes, however, are dissimilar with respect to size and sequence, with the exception of intron C in factor VII and protein C. The gene for factor VII also contains five regions made up of tandem repeats of oligonucleotide monomer elements. More than a quarter of the intron sequences and more than a third of the 3' untranslated portion of the mRNA transcript consist of these minisatellite tandem repeats.
活化因子VII(因子VIIa)是一种维生素K依赖的血浆丝氨酸蛋白酶,参与导致血液凝固的一系列反应。分离并鉴定了两个包含编码人因子VII序列的重叠基因组克隆。确定了该基因的完整序列,发现其跨度约为12.8千碱基。通过cDNA克隆证明,因子VII的mRNA在多个位点进行多聚腺苷酸化,但仅包含一个AAUAAA多聚(A)信号序列。该mRNA可进行可变剪接,形成一个包含八个外显子片段的转录本,另一个转录本带有一个额外的外显子,该外显子编码一个更大的前原导序列。后一种转录本在其他维生素K依赖蛋白中没有已知的对应物。因子VII的八个必需外显子所编码的氨基酸序列中内含子的位置与因子IX、因子X、蛋白C和凝血酶原的前三个外显子中的内含子位置相同。这些外显子编码该基因家族成员中通常保守的结构域。然而,这些基因中可比的内含子在大小和序列方面不同,因子VII和蛋白C中的内含子C除外。因子VII基因还包含由寡核苷酸单体元件串联重复组成的五个区域。超过四分之一的内含子序列和超过三分之一的mRNA转录本的3'非翻译部分由这些微卫星串联重复组成。